Feeding Polyphosphate to
Sequester Iron and Manganese

The recommended feed rate for most situations using ProPoly is to use one pound (1.5 cups) of ProPoly per 40,000 gallons of water. This produces a 2-parts- per-million phosphate result. Increase the feed rate to 1 lb per 20,000 gallons for water supplies with heavier than normal corrosion and iron.

Pump sizing and feed implications are as follows:

Assume that you have an irrigation system with a feed stream of 17 gallons per minute. If you mix one pound of polyphosphate with one gallon of water for your feeder you have a solution that is approximately 80,000 parts per million phosphate. If you apply these numbers to our pump-size calculator you will find that to achieve a 2 parts per million result you will need a pump that feeds at the rate of 0.6 or so gallons per 24 hours. You could, therefore, mix a pound of ProPoly with 2 gallons of water to produce a 40,000 ppm solution. Your pump would then need to put out about 1.22 gallons per day. Then you could use a 2 gallon per day Stenner pump and set the feed at a bit below the halfway mark.

The essential numbers are:

• One pound of ProPoly in a gallon of water makes an 80,000 ppm solution.
• One pound of ProPoly in two gallons of water makes a 40,000 ppm solution.
• The dosage desired for normal iron and corrosion control is about 2 parts per million. If corrosion is heavy, go as high as 4 ppm.